Pinocytosis is best described as

• A. Cell division
• B. Cell drinking
• C. Cell signaling
• D. Cell eating

Answer: (B)

Pinocytosis is a form of endocytosis in which the cell ingests extracellular fluid and dissolved solutes by forming small vesicles from the plasma membrane. It’s often called cellular drinking because the uptake involves fluid rather than solid particles. The process is generally non-specific, allowing the cell to sample its surroundings and acquire small molecules from the surrounding fluid. This differs from cell division, which is about duplicating the cell’s contents to form two cells, and from signaling, which uses receptors to relay messages without bulk uptake. It’s also different from phagocytosis, which involves engulfing larger particles such as debris or microbes.